IBM PS/1 486sx25 CPU Upgrade Help
Hello all,
I have been doing a bit of research and have decided that the best thing to do is to get a decent upgrade processor or FPU. However, I am unsure of what I should look at purchasing. The 486sx is a surface-mount quad-flatpack type soldered to the board, however the MBoard does have some sort of upgrade socket next to it. My best guess would be that this is a FPU socket to turn the 486sx into a dx chip of sorts. However, if at all possable, I'd like to get a Pentium OverDrive chip or one of those snap-on upgrade modules that disable the sx chip and use another CPU of your choice (I'll add an image of one later if anybody wants).
Thank you all for the help,
TheWalkingContradiction
PS: I will add some pictures of the MBoard socket later
I have been doing a bit of research and have decided that the best thing to do is to get a decent upgrade processor or FPU. However, I am unsure of what I should look at purchasing. The 486sx is a surface-mount quad-flatpack type soldered to the board, however the MBoard does have some sort of upgrade socket next to it. My best guess would be that this is a FPU socket to turn the 486sx into a dx chip of sorts. However, if at all possable, I'd like to get a Pentium OverDrive chip or one of those snap-on upgrade modules that disable the sx chip and use another CPU of your choice (I'll add an image of one later if anybody wants).
Thank you all for the help,
TheWalkingContradiction
PS: I will add some pictures of the MBoard socket later
Comments
(this is not from the machine, however I believe it to be the same socket...I will upload a new picture from inside the PS/1 once I am able to access it)
I used to have one of those in a 486 something or other.
At the time, my primary PC was a 486 dx100 that I had clocked at 120mhz, which I thought with my 64mb ram and 1mb video card was pretty rockin'...My how things have changed.
There is no such thing as a 487. Intel deceptively marketed their i487 as an optional FPU upgrade, but in reality it is a full-fledged (read: rebadged) 486DX that disabled the SX chip when inserted. In your case you can probably drop in the 63MHz Pentium overdrive since your board's bus speed is 25MHz.
DO NOT plug in a Cyrix or AMD 5x86 into that socket as these chips run at 3.45v. Intel SX, DX, and DX2 chips run at 5v.
If you need more help I would suggest visiting the VOGONS forum. They'll help you with any retro hardware questions you might have.
That's pretty sneaky, I actually didn't know INTeL did that kind of thing. It kind of makes sense though, because it adds extra manufacturing costs to make a separate chip just for upgrades, and I think it was done to save a bit of money.
Anyway, here's the picture of the socket I promised
I also added a heat sync to the chip using some aluminum foil tape, and it works pretty well.
I can't figure out what the socket is I thought it was socket 3 which was the socket for the 487 upgrade, but it has more pins than that socket unless i am counting the pins wrong. What socket is this? I can't find the socket anywhere, could this be the 486 overdrive socket?
Thats the pentium overdrive socket i believe, i think i figured out the socket, it was confusing me that it wasn't the same color as a standard socket 1 , it is a socket 1 which is for 486 overdrive processors and other 486 based processors, the blue socket is for pentium overdrive which will also take older cpu's, the black one is a overdrive 486 which will take 486 overdrive and older 486 cpu's
You're right, that is Socket 1, not 2. The blue socket (2) was for i486 Overdrives and Pentium Overdrives. You should be able to use a regular i486 Overdrive in that socket depending on which variant you have. One had 168pins, and the other had an extra 169th pin.
https://en.wikipedia.org/wiki/Intel_80486_OverDrive
I actually found a solution to this issue a while back, and I'd like to let you all know what I ended up doing. The socket that's in the picture I posted turned out to be a standard Socket 3, and I have added an intel i486DX33 (clocked at 25MHz) with a passive heatsync held down with some thermal compound.
Thank you for all your help everybody!
- TheWalkingContradiction